Manufacture of electric incandescent lamps



L. WITTEK MANUFACTURE OF ELECTRIC INCANDESCENT LAMPS May 30, 1950 2 Sheets-Sheet 1 Filed June 17, 1949 IN! EN TOR. LEsL/E W/TTEK DTTGRNE Y5 Patented May 30, 1950 MANUFACTURE OF ELECTRIC INCAN- DESCENT LAMPS Leslie Wittek, Belleville, N. J., assignor to Tung- Sol Lamp Works, Inc Newark, N. J a corporation of Delaware Application June 17, 1949, Serial No. 99,706

6 Claims.

This invention relates to the manufacture of electric incandescent lamps.

More particularly this invention relates to the basing of lamp bulbs and one object of the invention is a novel and improved method of grounding the ground wires to the shells of the bases during the basing operation resulting in a novel and improved incandescent lamp.

For a better understanding of the invention reference may be had to the accompanying drawings forming a part of this application, wherein Fig. 1 schematically illustrates steps in the preparation of the bases for the basing operation in accordance with the invention;

Fig. 2 illustrates schematically steps in the basing of the lamps in accordance with the invention;

Fig. 3 is an elevational view of a finished lamp embodying the invention;

Figs. 4 and 5 are views of a difierent type of miniature bulb prepared for the basing operation;

Fig. 6 is a plan view of a device or apparatus for preparing the bases for use in the manufacture of lamps in accordance with the invention;

Fig. 7 is a sectional view along the line l---| of Fig. 6;

Fig. 8 is a view similar to Fig. '7;

Fig. 6a is a plan view corresponding to Fig. 8; and

Fig. 9 is a cross-sectional view along the line 9-9 of Fig. 6.

In the conventional practice the base shells for miniature lamps are prepared for the wire attaching and grounding operation by forming notches at the peripheral edges of the sides of the shells. The ground wires which are to be grounded and fastened to the base shells are loosely positioned in these notches and are soldered therein and thereto. Excessive solder is required for this soldering operation and there are other disadvantages of this conventional practice.

In one aspect of my invention the base she ls are not notched but instead are slit at the peripheral edges with the edges of the slits bent outwardly, and the grounding operations are effected by causing the ground wires to be caught and tightly held between the edges of the sl ts before or at the time of the soldering operation. The outwardly projecting ends of the ground wires thus positioned and caught between the edges of the slits are severed by suitable wire clipping devices and a further aspect of the invention resides in the simultaneous clipping of the wires and the reshaping of the cylindrical shape of the shells by forcing the bent outward edges back into the approximate cylindrical positions.

Referring to Fig. 1 of the drawings I have 11- lustrated a conventional miniature lamp base I of the screw type having a substantially cylindrical or slightly flaring open end 2. Instead of forming a notch in the periphery of the shell 2 by removing a part of the material to form the notch, I form a longitudinal slit in the peripheral edge by utilizing a suitable knife 3 having a sharp cutting edge 3'. The knife 3 projects up into the bottom part 2 of the base shell and the slitting operation is performed by the knife 3, moving radially outward relatively to the shell as indicated in Fig. 1B. A slit 4 is thus formed, the edges of which slit 4 are indicated by the numeral 5. The base shell 2 in the vicinity oi the slit is upset slightly in the outward direction with the edges 5 of the slit assuming the relative positions indicated in Figs. 1C, 1D and 1E. It is observed that the edges 5 of the slit gradually curve outwardly to form a slit of gradually increasing dimensions from the innermost end of the slit to the outermost end thereof with opposite outwardly extending flare parts or ears 4'. The ground wire of the lamp bulb may be easily positioned within this slit 4 and with the wire positioned in the slit the edges 5 may be easily forced back into substantially cylindrical relationship with the rest of the shell with the wire firmly gripped therebetween.

In Fig. 2 I have illustrated the step of simultaneously severing the projecting end of the ground wire and pressing the edges 5 oi! the slit inwardly to firmly grip the ground wire. In Fig. 2A I have schematically illustrated a holder Ill for the miniature bulb i I, this holder being spring biased in an upward direction by a spring I2. I have also schematically illustrated at H a holder for the base shell I for holding the base shell in basing relation to the bulb l i during the basing operation. The ground wire of the lampbulb is indicated at l 5 and is positioned within the slit 4 of the she l ready for the final operation or operations of severing the projecting end of the ground wire l5 and smoothing out the upset part of the base shell. In Fig. 2B I have schematically illustrated a sectional view through the bulb I l at a point just below the peripheral edge of the shell, looking upwardly into the slit 4 whose edges 5 are bent outwardly with respect to the shell. I have schematical y illustrated a pair of severing and clipping knives l6, these knives l6 being oneratively disposed in a position to simultaneously sever the projecting end 01 the ground wire l5 and asse ses to brad inwardly or smooth out the upset portion of the shell in the vicinity of the slit. The knives l6 are wide enough to engage the whole upset portion of the periphery of the shell and when these knives are operatively brought together or in a direction toward each other, they engage the slantingedges 2' of the upset portion of the periphery of the shell to press the upset portions into their approximate cylindrical relationship to the rest of the shell. Thus the projecting or surplus endoi the ground wire I is severed simultaneously with the smoothing out of the upset peripheral edge caused by the slitting operation. Fig. 2C indicates the knives IS in the position of just having severed the ground wire l5 and it is observed that the bent or deformed edges 2 of the shell periphery are now brought into positions where they form a substantial continuation of the cylindrical surface of the shell.

The ground wire is thus gripped by the peripheral edges 5 of the slit and mechanically and firmly held in electrical engagement with the shell. If desired the wire may be soldered at the slit.

Fig. 3 is an elevational view of the finished wire groundin operation.

In Figs. 4 and 5 I have shown a smooth base shell 20, not provided with a screw attachment, which is suitable for certain types of miniature lam'ps. This base is designed for a two-filament lamp shell being two apertures 2| in the closed end of the shell for the reception and soldering of the wires leading to the two different filaments. At IS in Fig. 2A I have illustrated a wire for forming the electrical connection at the closed end of the base.

Referring to Figs. 6 to 9 I have illustrated a means for forming the slits 4 in the base shells. In these figures the base shell I, 2 is held immovably while the slitting knife 3 is movable to form the slit 4 in the base shell. The knife 3 is carried by a slide member 25 which is slidable in a guiding recess or opening formed in the frame member 26. The slide member 25 is provided with a main body part 21 having a recess 28 formed on one side thereof for the reception of a mating clamping member 29, the latter being fastened to the main body 21 in any suitable manner as, for example, by the bolts 30. The slitting knife 3 is firmly clamped between the members 21 and 29 and the members 21 and 29 are provided respectively with recesses 21' and 23' for the reception of the knife 3. The upper edge of the knife 3 projects through the upper part 26' of the frame, namely through a slot 3| formed therein which permits relative movement between the slide 21 and the frame member 26. The upper part 26 of the frame member is provided with an annular shoulder 32 for the reception of the shell 2 of the base, the latter being held tightly against the upper side of the frame member 26 during the slitting operation as, for example, by being held manually thereagainst. The shell 2 fits somewhat loosely over the shoulder 32 and the latter prevents lateral or sidewise movement of the base shell during the movement of the slide 25 to form the slit.

To the main body 21 of the slide is fastened ayoke comprising a cross member 35 which is fastened to the slide in any suitable manner as, for example, by a screw bolt 36. The cross piece 35 of the yoke is recessed at 35 to receive the right-hand end of the slide member 21. A pair of pins 38 is fastened to and carried by the mem her 35 and biasing springs 39 surround these pins and engage the inner surface of the member 35 at one end while the other ends of the biasin springs are disposed in recesses 46 formed in the right-hand end of the frame member 26 at points on opposite sides of the guideway for the slide member 25, 21, 29. By these biasing springs the knife 3 is normally held in the position shown in Figs. 6 and 7 but may be moved against the tension of the springs 39 to the position indicated in Figs. 6A and 8 for forming the slit 4 in the base shell 2.

The upper member 26' of the frame is formed separately from the frame member 26 and is clamped or fastened thereto by any suitable means as, for example, the bolts 42. A pair of hardened blade members 45 are fastened in any suitable manner on the upper side of the frame member 26, the inner ends of these blade members being provided with tapered projections 50 disposed adjacent the shell 2 and in a position to function as a back stop for the flared portions 4' of the slit 4. The upper inner edges 5| of these projections 56 converge inwardly in a direction away from the base shell and the end surfaces 50' of these projections diverge slightly from each other in a downward direction, and also converge toward each other in a direction away from the base shell. These end surfaces 50 thus formed function as bearing surfaces for the opposite upset parts 48 of the shell slit both to assist in the formation of the slit and to provide slits which are uniform in dimensions and smoothness.

The blade members 45 are clamped between the shoulders 46 formed on the main frame member 26 and corresponding and cooperating shoulders 46' are likewise formed on the frame member 26. The blade members 45 are clamped in their adjusted positions by means of pairs of bolts 48 screw-threadedly attached to and passing through the shoulders 46. A filler strip 41 of comparatively soft metal is interposed between the inner ends of the bolts 48 and the blade members 45 Fig. 6A and Fig. 8 illustrate the position of the slide 21 during the slitting operation, the position shown being that at or near the finishing of the slitting operation. The edge of the base shell is thus severed to form the slit 4 with the opposite upset parts 4 of the slit portion Of the-shell being forced out against the bearing surfaces 50', II.

I claim:

1. A miniature incandescent electric lamp having a base shell and a ground wire, the shell having a slit formed in the periphery thereof with the ground wire caught between the'juxtaposed edges of the slit.

2. An electric incandescent lamp having a metallic base shell and a ground wire, said shell having its peripheral edge slitted with the ground wire caught firmly between the adjacent edges of the slit.

3. The method of making a miniature incandescent lamp having a metallic shell base and a ground wire which comprises the step of slitting the peripheral edge of the base shell and positioning the ground wire within the slit to be firmly engaged by the edges of the walls of the slit.

4. The method of making an electric incandescent lamp having a metallic shell base and a ground wire to be grounded to said base shell which comprises the steps of forming a slit in the peripheral edge of the base shell with the edges of the slit upset outwardly and diverging from each other, positioning the ground wire in said slit with the end thereof projecting beyond theshell and then pressing the upset part of the shell inwardly to form a continuation of the shell circumference with the ground wire caught firmly between the edges of the slit.

5. The method of making an electric incandescent lamp having a metallic shell base and a ground wire to be grounded to said base shell which comprises the steps of forming a slit in the peripheral edge of the base shell with the edges of the slit upset outwardly and diverging from each other, positioning the ground wire in said slit with the end thereof projecting beyond the shell and then pressing the upset part of the shell inwardly to form a continuation of the shell circumference with the ground wire caught firmly between the edges of the slit and soldering the wire to the slitted edges of the shell.

6. The method of making an electric incandescent lamp having a metallic shell base and a ground wire to be grounded to said base shell which comprises the steps of forming a slit in the peripheral edge of the base shell with the edges of the slit upset outwardly and diverging from each other, positioning the ground wire in said slit with the end thereof projecting beyond the shell and then simultaneously pressing the upset portion of the shell inwardly to form a substantial continuation of the shell surface and severing the projecting end of the wire with the wire caught firmly between the edges of the slit.

LESLIE WIT'I'EK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,204,273 Hale June 11, 1940 20 2,320,272 Friden May 25, 1943 2,338,865 Matson Jan 11, 1944 2,370,063 Brown et al June 26, 1945 

